diff --git a/src/libcore/tests/lib.rs b/src/libcore/tests/lib.rs index 71a061af28920..05f958cbe81fe 100644 --- a/src/libcore/tests/lib.rs +++ b/src/libcore/tests/lib.rs @@ -41,6 +41,7 @@ #![feature(never_type)] #![feature(unwrap_infallible)] #![feature(leading_trailing_ones)] +#![feature(const_forget)] extern crate test; diff --git a/src/libcore/tests/mem.rs b/src/libcore/tests/mem.rs index 59588d97787b7..8337ab103419f 100644 --- a/src/libcore/tests/mem.rs +++ b/src/libcore/tests/mem.rs @@ -129,3 +129,21 @@ fn test_discriminant_send_sync() { is_send_sync::>(); is_send_sync::>(); } + +#[test] +fn test_const_forget() { + const _: () = forget(0i32); + const _: () = forget(Vec::>>::new()); + + // Writing this function signature without const-forget + // triggers compiler errors: + // 1) That we use a non-const fn inside a const fn + // 2) without the forget, it complains about the destructor of Box + const fn const_forget_box(x: Box) { + forget(x); + } + + // Call the forget_box at runtime, + // as we can't const-construct a box yet. + const_forget_box(Box::new(0i32)); +}